Antiphospholipid Syndrome

Question 1

What are antiphospholipid antibodies?

Answer 1

A family of autoantibodies directed against phospholipid-binding plasma proteins, most commonly β2-glycoprotein I.

Question 2

What are some classic hallmarks of APS?

Answer 2

you diagnose based on clinical features:

• thrombosis history (arterial OR venous)
• spontaneous abortions AFTER 10 weeks

Question 3

What is the classic presentation of arterial thrombosis in APS?

Answer 3

stroke

Question 4

What is the classic venous manifestation of APS?

Answer 4

DVT

Question 5

What does diagnosis of APS require?

Answer 5

that a patient have both a clinical event (thrombosis or pregnancy morbidity) and the persistent presence of antiphospholipid antibody (aPL), documented by a solid phase serum assay [anticardiolipin or anti-β-glycoprotein (Anti-β2GPI) immunoglobulin (Ig)G or IgM, a coagulation assay (inhibitor of phospholipid-dependent clotting-the lupus anticoagulant test], or both

Abs should be there 12 weeks apart

Question 6

Anti-phospholipid antibodies are not specific to APS. When else can they be seen?

Answer 6

10% to 40% of SLE patient and approximately 20% of RA patients have a positive aPL test

Question 7

What are some other clinical features that suggest APS?

Answer 7

• livedo reticularis
• thrombocytopenia (50-100k)
• autoimmune hemolytic anemia
• cardiac valve disease
• MS-like syndrome, chorea

Question 8

Abs for APS?

Answer 8

• IgA anticardiolipin antibody
• IgA anti-B2 glycoprotein I

not as pathologic as the IgG

Question 9

Treatment for APS?

Answer 9

systemic anticoagulation

Question 10

Question 11

Give a quick rundown on the workup of a suspected APS patient

Answer 11

1) History- any miscarriages (how many weeks in?); face drooping, arm weakness/numbness, slurred speech? How active are you? any swollen legs? Skin rashes? Fatigue? Check
2) Physical: look for livedo reticularis; Homan’s sign (below; push ankle toward patient to elicit pain); Coomb’s test
3) Labs: anti-glycoprotein 1; anticardiolipin IgA; CBC (check for thrombocytopenia, increased bilirubin or LDH, reduced haptoglobin and urine hemoglobin
4) Imaging: brain CT

Question 12

Quick rundown of AHA

Answer 12

AIHA can be caused by a number of different classes of antibody, with IgG and IgM antibodies being the main causative classes. Depending on which is involved, the pathology will differ. IgG is not very effective at activating complement and effectively binds the Fc receptor (FcR) of phagocytic cells, AIHA involving IgG is generally characterized by phagocytosis of RBCs. IgM is a potent activator of the classical complement pathway, thus, AIHA involving IgM is characterized by complement mediated lysis of RBCs. IgM also leads to phagocytosis of RBCs however, because phagocytic cells have receptors for the bound complement (rather than FcRs as in IgG AIHA). In general, IgG AIHA takes place in the spleen, whereas IgM AIHA takes place in Kupffer cells – phagocytic cells of the liver. Phagocytic AIHA is termed extravascular, whereas complement-mediated lysis of RBCs is termed intravascular AIHA. In order for intravascular AIHA to be recognizable, it requires overwhelming complement activation, therefore most AIHA is extravascular – be it IgG- or IgM-mediated.